When shopping for a portable air conditioner, you may have come across the foreign acronym “BTU.” It appears not only in every product description but also in many product names. It is obvious that this is important to understanding portable air conditioners, but it is not clear why that is and why it should matter to you.
B-T-U
The acronym stands for British Thermal Unit, which is the unit used to measure thermal (heat) energy. Specifically, it is the amount of energy needed to raise 1 pound of water 1°F at sea level.
Click Here to View All Portable Air ConditionersWhen used in relation to air conditioning systems or heaters, the measurement is expressed in terms of how many BTUs per hour the product can add or remove from the air.
With that said, unless you are involved in the manufacturing or retailing of cooling and heating supplies, this may not mean anything to you. But it should, and here’s why:
Too Much of a Good Thing
A higher number of BTUs isn’t always the answer. Using a portable air conditioner with a BTU level higher than needed can cause the unit to cool quickly, cycle off and then, to maintain your desired temperature, have to cycle on again soon after. By cycling on and off in such fitful spurts of time, your portable air conditioner’s compressor will quickly over-work itself. If done excessively and frequently, you will likely shorten your unit’s lifespan.
This is not exclusive to portable AC units, either. The same goes for all AC units, including the popular window and central air conditioners as well.
Too Little, Too Late
Using a portable air conditioner with not enough recommended BTUs will keep you from reaching your desired comfort level. The heat load will be too much for your unit to handle. This will cause your AC unit to run continuously and never reach your set temperature level. Not to mention shorten its lifespan.
This is why it is important to pay attention to square footage recommendations per the each air conditioner you considering of buying. As well as have a pretty good idea of the square footage of the space you are intending to use the AC unit in.
BTU Recommendations Based on Square Footage:
We would recommend using our BTU cooling calculator to determine the specific amount of BTUs you will need from your air conditioner in order to properly cool your space. However, below we have listed some general BTU recommendations that will help get you started.
BTU Chart Based on Room Size
Room Size BTU’s Needed Room Size BTU’s Needed 150 sq. ft. 5,000 BTU’s 700 sq. ft. 14,000 BTU’s 250 sq. ft. 6,000 BTU’s 1,000 sq. ft. 18,000 BTU’s 300 sq. ft. 7,000 BTU’s 1,200 sq. ft. 21,000 BTU’s 350 sq. ft. 8,000 BTU’s 1,400 sq. ft. 23,000 BTU’s 400 sq. ft. 9,000 BTU’s 1,600 sq. ft. 25,000 BTU’s 450 sq. ft. 10,000 BTU’s 1,900 sq. ft. 28,000 BTU’s 550 sq. ft. 12,000 BTU’s 2,700 sq. ft. 36,000 BTU’sOther Important Factors to Consider:
Although square footage recommendations are typically correct, there are some other confounding variables that you should pay attention to when looking at the BTU’s of your air conditioner.
If you are attempting to cool a second story that is typically warmer than the ground floor or a space that gets a lot of direct sunlight (for example, a room with a large west-facing window), you want to add 10% of the recommended BTUs. After adding 10%, you will have a better estimate of the cooling power you will need for this space. This is due to the added ambient heat added due to the environment. This may mean going up to the next available cooling power.
On the other hand, if the area you are going to be cooling has lots of shade and very little sunlight exposure, you may want to consider subtracting 10% of the recommended BTU. This is not always recommended, as it is better to have too many BTU’s than not enough.
If there is going to be more than two people in the area at a time, you should add approximately 600 BTUs per additional person.
If you plan on using your air conditioner in your kitchen, or any area of your home where your appliances will likely generate higher levels of heat, you will need to add 4,000 BTUs to the recommended cooling power.
Lastly, you want to consider whether or not your space is open or confined. Our square footage recommendations are meant for confined areas, so if your room open ups into another space without the option of closing a door, you will want to add in that other space. For example, if you want to cool a kitchen that opens into a living room, you will want to combine the size of those two rooms as if they were one space and use that as your determinate square footage.